The present invention relates to an aerodynamic fairing of the rear section of an aircraft pylon, likewise referred to as the aft pylon fairing or APF.
In a known manner, the aerodynamic fairing takes the shape of a box comprising two side panels assembled to each other by transverse stiffening frames spaced apart from one another along the longitudinal axis of the fairing, as well as a heat protection deck fixed on the one hand to the side panels and on the other to the frames.
An aft pylon fairing is exposed to high temperatures coming from the aircraft's powertrain assembly. In particular, the heat protection deck is subjected to a high-temperature primary flow from the turbojet (in the order of 600° C.), while the side panels are subjected to a secondary flow from the turbojet with a relatively low temperature (in the order of 150° C.) compared with that of the primary flow. These temperature differences generate high thermo-mechanical stresses on the box which tend to deform it.
French patent document FR1361556 discloses an aerodynamic fairing comprising a deck formed by consecutive portions disposed along the longitudinal axis of the fairing, each portion being directly fixed to a first frame and to a second frame directly consecutively to the first. The fact that there is a longitudinal mechanical cut-off between two consecutive deck portions means that each deck portion has its own heat expansion, something that helps to reduce the thermo-mechanical stresses acting on the box. Moreover, to prevent the high-temperature primary flow from rising and spreading in the interfaces between two consecutive deck portions, the heat protection deck is made leak-proof by thin strips fixed to the outer face of the deck portions in such a manner as to cover said interfaces and guide the primary air flow along the outer faces of the deck portions. These thin strips are effective but, on the other hand, they have to be installed on the deck portions by means of screws which complicates and slows down the fabrication of the aerodynamic fairings.